Sulphides of alkylated phenols



- phenols.

2398.253 1 a SULPHIDES or ALKYLATED rumor Dilworth '1'. Rogers, Teaneck,and Herman Feldhusen, Jr., North Plainfield, N. J., assignors-toStandard Oil Development Company, a corporation of Delaware No Drawing.Application June 20, 1944,

, Serial No. 541,299 a 16 Claims. (01.:260-137) Y .This inventionrelates to the manufacture of sulphides of alkylated hydroxy aromaticcompounds and especially the sulphides of alkylated The sulphides ofalkylated to be particularly useful as lubricating oil additives. Thealkyl phenol sulphides are generally phenols and the-like, and likewisetheirmetal salts, have been found prepared on a commercial scale byalkylating a phenol with an olefin in the presence of a catalyst andthen further reacting the alkylated phenol, generally in thepresence ofa solvent, with a halide or oxyhalide of sulphur, such as constitute aclass of catalysts which will eiliciently promote the alkylation ofphenols and will at the same time permit the use of hydrocarbon solventsin the sulphurization step without the formation'of objectionablesludge, even though the alkylation catalyst is not removed from thealkylated phenol. It has been discovered that the halides of boron andcomplexes containing these compounds are not only emcient alkylationcatalysts, but also -act as catalysts to a certain degree in thesulphurization step, and, depending on reaction conditions, eitherproduce no sulphur monochloride, sulphur dichloride, thionyl chloride orsulphuryl chloride. As an example of this process, a tert.-oct'yl phenolis prepared by reacting diisobutylene with a phenol, and the product isreacted with sulphur dichloride to produce chiefly the monosulphide oftert.-ootyl phenol. A serious practical problem involved in this processis the presence of the alkylation catalyst in the alkylated phenol afterthe alkylation reaction has been completed. Some Friedel-Crafts typecatalysts, for example,'if allowed to remain in the alkylated phenolproduct during the treatment with a sulphur chloride, frequently promotechlorination of the product in addition to sulphurization.

sludge at all in the presence of a hydrocarbon solvent orproduce only agranular powder which does notadhere to the walls of the reaction vesseland therefore does not interfere with the handling of the phenolsulphide solutions. The boron halides, particularly boron trifiuoride,have been found to be particularly useful in the reaction of the'alkylated phenols with sulphur halide. Without a catalyst, thisreaction is usually preceded by an incubation period and then beginswith violence,- causing dimculties in operation. The

Because of the'adverse effects produced by the presence of suchcatalysts it is necessary to remove them fromthe alkylated phenolsbefore 7 tion step would be advantageous since it would greatly simplifymanufacturing operations by eliminating the step of removing thecatalyst. It has been found that stannic chloride is such a catalyst butthat it is of only limited ability, that is, its use must be confined tosulphurization reactions conducted in chlorinated solvents such aschloroform, ethylene dichloride or carbon tetrachloride. when employingpetroleum hydrocarbon solvents, which are economically much morepreferable, it was found that a large amount of tarry sludge wasproduced when the alkylated phenols (containing stannic chloridecatalyst) were sulphurized with sulphur halides. This sludge isparticularly objectionable in the commercial manufacture of alkyl phenolsulphides because it tends to clog the outlet valves of the reactionvessels and is difficult to remove. Frequent cleaning of reactionvessels is thus necessary which consequently impairs productionemciency. It has now been found that the halides of boron presence ofthe boron halide catalyst causes the reaction to begin promptly and toproceed smoothly throughout its course. It is thus not only unnecessaryto remove this catalyst, but it is highly desirable to retain the samein the alkylated phenol product because of its assistance in thesulphurization step.

Furthermore.. he presence of the boron halide also promotes theformation of alkylated phenol sulphides of more desirable properties.-In the reaction of alkyl phenols with sulphur halides it is generallythe case that a mixture of compounds is formed rather than oneparticular chemical compound, that is, in addition to the alkyl phenolsulphide itself polymeric materials are also usually present. This isnormally desirable when the products are to be employed as lubricatingoil additives since the pure crystalline alkyl phenol sulphides are notas oil-soluble as the polymeric type mixtures. To promote the formationof the latter type of material it is therefore usually more desirable toemploy more than the theoretical 1:2 mole ratio of sulphur halide tophenol. Nevertheless, in spite of this some pure crystalline alkylphenol sulphide does form under normal. circumstances. It has now beenfound that when sulphurization is conducted in the presence of boronfluoride catalyst the formation of crystalline material is almostcompletely eliminated. thus giving a higher yield of usable product.

As stated above, under certain conditions the boron halide catalyst doesnot produce any sludge or precipitate when sulphurizingaikylated'phenols in hydrocarbon media. This favorable condition isusually secured by first adding the boron halide catalyst to the phenoland then introducing the olefin in the alkylation stage. This method ofconducting the process insures a minimum amount of free phenol in thealkylation product, and with a substantially pure alkylated phenollittle or no sludge formation or precipitation takes place.

The present invention applies not only to the alkylation of the phenolitself, but to the alkylation of other monohydroxy aromatic compounds,particularly the alkylated phenols, naphthols and other monohydroxyaromatic hydrocarbons. The invention applies likewise to the alkylationof compounds of the class described which contain substituted atoms orgroups which do not interfere with the alkylation reaction, such asether, ester, keto, aldehyde, other alkyl groups, and the like. Theinvention is also applicable to the alkylation of aromatic esters,ketones, ethers, etc., per se, that is regardless of whether they alsocontain phenolic hydroxyl groups.

Included also are the high molecular weight alkylated phenols which maybe Prepared by condensing phenols with chlorinated petrolatum orchlorinated paramn wax or with a chlorinated kerosene or gas oil.Naturall occurring phenols such as those obtained by alkaline extractionof certain petroleum stocks or those obtained from cashew nut shellliquid or those obtained from other vegetable oil sources may likewisebe used.

Any of the olefins may be used for alkylation, such as the individualolefins or olefin-containing mixtures derived from petroleum sources,such as refinery gases containing propylene, butylenes, amylenes, etc.,also olefin polymers such as diisobutylene, triisobutylene or n-butenepolymers obtained as by-products in the manufacture of butyl alcoholfrom petroleum refinery butenes.

The catalysts preferred for use in accordance with the present inventionare the boron halides, especially boron trifluoride and complexescontaining the same, such as the combinations of boron trifluoride withwater and with phosphoric acid, although only very limited amounts ofwater may be tolerated in the sulphurization reaction. Hydrogen fluoridemay similarly be used.

As has been stated above, the preferred method of carrying out thealkylation reaction consists in first adding the catalyst to the phenoland subsequently adding the olefin. This procedure results in a muchmore complete conversion of the phenol to alkylated phenol than when thecatalyst is added to a mixture of the olefin and phenol. This may beshown clearly in the following data, obtained in a process of reactingequal molecular proportions of diisobutylene and phenol at 180 C., usingin each case 0.5% of boron trifluoride based on the total reactants, andconducting the reaction for 60 minutes:

Of special interest is the application of the present invention to theproduction of the sulphide of tert.-octyl phenol by the reaction ofdiisobutylene with phenol and the subsequentreaction with sulphurdichloride. The conditions best suited for conducting this process havebeen investigated in considerable detail, particularly with regard tothe conditions required to produce an alkylated phenol containing aminimum amount of unchanged phenol. Separate studies have been made ofthe efiect of reaction time, reaction temperature and catalystconcentration.

In all these studies a 1:1 mol ratio of olefin to phenol was employed.It should be understood, however, that other ratios may also be employedin practicing the invention. In general, if excess olefin is employed alower melting point crude alkylated phenol product is obtained, but atthe same time the product contains less non-alkylated phenol. If excessphenol is employed over the 1:1 ratio, dialkylation, i. e., formation ofdialkyl phenol in addition to the monoalkylated products, is minimized.

In a study directed to the determination of the best reaction time, thealkylation reactions were carried out with 0.5% boron fluoride, based onthe total reactants present, the catalyst being first added to thephenol and the reactions bein conducted at 50-90 C. The results are asfollows:

Table II Percent unchanged phenol in crude product Time for olefinaddition, min.

1 Stirred 10 minutes after olefin addition.

Table III Time to: Additional olefin addireaction 33 f g tion, min.time, min. e p oo 1 Melting point of pure tert.-oetyl phenol =86 C.

I Partly liquid at room temp. This breakdown of the product was alsonoted in an experiment in which pure tert.-octyl phenol was heated for 1hour at 90 C. with 1% boron fluoride. Under these conditions a liquidproduct containing 3% tree phenol was obtained.

It may thus be observed that the rate of olefin addition must be fairlyrapid and yet not too much so; too slow a rate ot addition causesisomerization of the alkylated phenol and too rapid a rate causespolymerization of the olefin before it has had an opportunity to enterinto the alkylation reaction. Furthermore, the reaction must not beallowed tocontinue for any great length of time after the olefin hasbeen added,

hydrocarbon solvent. as to;- example. a petroleum since this will alsocause isomerization of the alkylated phenol. The reaction can mostconveniently be stopped by adding a solvent to the reaction mixture tocool it rapidly. A suitable solvent would be one that can be employed inthe next step, i, e., sulphurization of the alkyl phenol with a sulphurhalide.

The effect of reaction temperature in the alkylation reaction to producetert.-octyl phenol, using boron trifluoride as a catalyst, was studiedin the temperature range of 70-90 C. When o erating with 0.5% borontrifiuoride, based on the total reactants, and adding the olefin over aperiod of 90 minutes, with an additional 30 minutes stirring time, themelting range of the tert.-

octyl phenol was found to be approximately the same when prepared ateither 70 C. or 90 6., although the lower temperature favors a lowerercentage of unreacted phenol in the product. The reactions wereconducted, as before, with equal molecular proportions of diisobutyleneand phenol. .The results a e shown in the iollowin table:

Table IV Temp Tami) Crude reaction product during during g lgggf olefinadditional stirring Percent addiion, Stlglgllg, mm reactedMeltiigsrange, phenol The efiect of catalyst concentration in thisreaction was also studied. Results obtained in alkylations conducted at90 C. with an olefin addition time of 90 minutes indicated that anincrease in boron fluoride concentration has an adverse efiect on thequality of the product, as judged by the melting point. Below are givendata obtained by conducting the reactions at a temperature of 5090 C.during the olefin addition and maintaining a temperature of 90 C.

during additional stirring, equal molecular proportions of olefin andphenol being used.

In summary, the optimum conditions for the production of the bestpossible grade of tart.- octyl phenol are the following: (1) addition ofthe boron fluoride to the phenol before the addition of the olefin; (2)addition of the olefin rapidly, preferably in minutes or less; (3)conducting the reaction for only a short period (10 minutes or less)after the olefin has been added; (4) a reaction temperature notexceeding 70 0.; and (5) a catalyst concentration not greater than 0.5%,based on the total reactants.

For the subsequent sulphurization of the tart.- octyl phenol prepared asdescribed above, using sulfur dichloride as the reagent for producingchiefly the monosulphide product, the tert.-octyl phenol, containing theboron halide catalyst, may

naphtha boiling in the range or IMP-865 F. or an aromatic type solventboiling at 200-280 F. and containing 65-70% or aromatic hydrocarbonsobtained in the cracking and dehydrogenation of petroleum oils. Thesehave been found to be particularly suited for the production 01' atert.-octyl phenol sulphide which is to be converted to a 20 to 40 C.

In general, the best results are obtained if the sulphurizationiscarried out rapidly and if cilicient agitation is employed. The moleratio of sulphur halide to alkyl phenol may be in the range of 1:2 to2:2 and for most purposes is preferably from 1.3:2 to 1.6 :2 when theproducts are to be used as such as lubricating oil additives or it theyare to be esterifled or converted to metal salts and employed aslubricating oil additives in such modified form.

The invention is not to be considered as limited by any of the examplesdescribed above. which have been presented for illustrative p p sesonly. but solely by the terms of the appended claims.

'We claim:

1. The process of preparing a sulphide 01' an alkylated monohydroxyaromatic compound which comprises almlating a monohydroxy aromaticcompound with an olefin in the presence of a'boron halide-containingoatalyst, dissolving the reaction product containing said catalyst inasolvent, and treating the solution thus formed with a sulphur halide.

2; The process of preparing a sulphide of an alkylated monohydroxyaromatic hydrocarbon which comprises alkylating a monohydroxy aromatichydrocarbon with an olefin in the presence of a boron halide-containingcatalyst, dissolving the reaction product containing said catalyst in asolvent, and treating the solution thus formed with a sulphur halide.

3. The process of preparing a sulphide of an valhlated phenol whichcomprises alkylating a phenol with an olefin in the presence of a boronhalide-containing catalyst, dissolving the reaction product containingsaid catalyst in a solvent, and treating the solution thus formed with asul- Dhur halide.

4. A process according to claim 3 in which the solvent is a hydrocarbonsolvent.

5. The process of preparing a sulphide of an alkylated phenol whichcomprises adding boron trifiuoride in catalytic proportions to a phenol,thereafter alkylating the phenol with an olefin, dissolving the productof the alkylation reaction, containing the said catalyst, in a solvent,and treating the solution thus formed with a sulphur chloride.

6. The process of preparing a sulphide of tert.- octyl phenol whichcomprises adding boron trifluoride in catalytic proportions to phenol,thereafter alkylating the phenol with diisobutylene,

dissolving the product 0! the alkylation, conbe dissolved in a suitablesolvent, preferably a is taining the boron trifiuoride, in a hydrocarbonwith sulphur dichloride.

7. A process according to claim 6 in which the phenol and diisobutyleneare reacted in substantially equal molecular proportions.

8. A process according to claim 6 in which. the boron trifiuoride ispresent in an amount not greater than about 0.5%, based on the totalreactants present. 1

9. A process according to claim 6 in which the temperature of thealkylation reaction is not greater than about 70 C.

10. A process according to claim 6 in which the diisobutylene is addedto the phenol during a period not greater than about 15 minutes and inwhich the reaction is not allowed to continue for more than about 10minutes after the diisobutylene has been added.

11. The process of preparing a sulphide of tert.-o-ctyl phenol whichcomprises adding a boron trifiuoride catalyst to phenol, thereaftertreating the mixture thus formed with diisobutylene in an amount whichis substantially equal in molecular roportionto the phenol present at atemperature not greater than about 70 0., the amount of borontrifluoride used being not greater than about 0.5%, based on the totalweight of the phenol and diisobutylene present, adding the diisobutyleneto the phenol during a period not greater than about minutes andpermitting the reaction to continue for a period not greater'than about10 minutes after addition of the diisobutylene, dissolving the productof the alkylation, containing the boron fluosolvent, and treating thesolution thus formed ride, in a hydrocarbon solvent in a concentrationequal to about 40 to and treating the solution thus formed with sulphurdichloride at a temperature of about 20 to about 40 C.-

12. A process according to claim 11 in which the hydrocarbon solvent isa naphtha of about 190-265 F. boiling range.

13.'A process of preparing tert.-octyl phenol which comprises adding aboron trifluoride catalyst to phenol, thereafter treating the mixturethus formed with an amount of diisobutylene which is substantially equalin molecular proportion to the phenol present at a temperature notgreater than about (2., the amount of boron trifluoride used being notgreater than about 0.5%, based on the total weight of the phenol anddiisobutylene present, adding the diisobutylene over a period notgreater than about 15 minutes and continuing the reaction for a periodnot greater than about 10 minutes aftersuch addition of diisobutylene.

14. The process of preparing an alkyl phenol sulphide comprising thereaction of an alkyl phenol with a sulphur halide in the presence of aboron halide catalyst.

15. The process of preparing'tert.-octyl phenol sulphide comprising thereaction of tert.-octyl phenol with sulphur dichloride in the presenceof a small amount of boron trifiuoride.

16. A process according to claim 15 in which the reaction is conductedin a hydrocarbon solvent. DILWORTH T. ROGERS.

HERMAN FELDHUSEN, JR.

